Waterproof Roofing Installation
Rosario, Naranjo, Costa Rica – February, 2020
There are a variety of options when selecting roofing materials for dwellings in Costa Rica.
The majority of the roofs here are covered with thin corrugated metal laminates attached directly to the roof structures, without waterproof sheathing or underlayment to protect the interiors of the homes from exterior moisture and the extreme ultraviolet radiation from being only 10 degrees north of the equator.
Recently, I’ve been building a house, and I’m sharing the following roofing and waterproofing materials and installation methods that I selected.
I installed a galvanized metal roof structure, welded to the main concrete beam on top of the walls of the house.
Then I screwed 20 mm (3/4″) thick, Plycem fiber cement laminates to the metal roof structure
Maxiflex 40 polyurethane sealer was applied to the joints and underneath the laminates for expansion control and adhesion to the metal structure
Aquaprimer, asphalt solvent-based primer was applied to the fiber cement laminates, to seal the porosity of the surface and increase the adhesiveness to the waterproofing membrane
A 4 mm thick, white, waterproofing membrane, fabricated with modified asphalt and polyolefin-elastomeric polymer (APP), was heat welded to the fiber cement laminates
Solartex acrylic sealer was applied to the membrane to protect the surface and to help reflect ultraviolet rays
This finished surface of membrane attached to the fiber cement laminates is more than adequate to protect this house from the elements in Costa Rica.
If an additional finished roof surface is desired, such as clay tiles, they can be installed on top of the membrane without problems, because I constructed the roof structure sturdy enough to support more weight.
The builder, Tom Rosenberger has lived and worked in Costa Rica since 1992 and from his travels throughout the country inspecting and constructing housing, he has acquired a wealth of knowledge about roofing and construction in Costa Rica. If you have questions and would like to contact Tom click here.